Stockholders' Equity (Details 1) (USD $)	12 Months Ended
	Dec. 31, 2012
Summarizes information with respect to stock options outstanding
Number of Shares Outstanding and Exercisable	9,184,346
Options outstanding Weighted-Average Remaining Contractual life	6 years 5 months 16 days
Number of Shares Exercisable	6,435,730
Options exercisable Weighted Average Exercise per Share Price	$ 6.62
Range 1 [Member]
Summarizes information with respect to stock options outstanding
Lower Range of Exercise Price	$ 2.04
Upper Range of Exercise Price	$ 3.42
Number of Shares Outstanding and Exercisable	366,394
Options outstanding Weighted-Average Remaining Contractual life	8 years 3 months 22 days
Number of Shares Exercisable	107,603
Options exercisable Weighted Average Exercise per Share Price	$ 2.55
Range 2 [Member]
Summarizes information with respect to stock options outstanding
Lower Range of Exercise Price	$ 3.45
Upper Range of Exercise Price	$ 3.45
Number of Shares Outstanding and Exercisable	1,613,813
Options outstanding Weighted-Average Remaining Contractual life	5 years 11 months 9 days
Number of Shares Exercisable	1,613,813
Options exercisable Weighted Average Exercise per Share Price	$ 3.45
Range 3 [Member]
Summarizes information with respect to stock options outstanding
Lower Range of Exercise Price	$ 3.61
Upper Range of Exercise Price	$ 5.19
Number of Shares Outstanding and Exercisable	1,045,182
Options outstanding Weighted-Average Remaining Contractual life	3 years 8 months 1 day
Number of Shares Exercisable	912,138
Options exercisable Weighted Average Exercise per Share Price	$ 4.47
Range 4 [Member]
Summarizes information with respect to stock options outstanding
Lower Range of Exercise Price	$ 5.26
Upper Range of Exercise Price	$ 5.30
Number of Shares Outstanding and Exercisable	7,500
Options outstanding Weighted-Average Remaining Contractual life	8 years 11 days
Number of Shares Exercisable	1,500
Options exercisable Weighted Average Exercise per Share Price	$ 5.30
Range 5 [Member]
Summarizes information with respect to stock options outstanding
Lower Range of Exercise Price	$ 5.35
Upper Range of Exercise Price	$ 5.35
Number of Shares Outstanding and Exercisable	1,126,273
Options outstanding Weighted-Average Remaining Contractual life	6 years 11 months 5 days
Number of Shares Exercisable	838,523
Options exercisable Weighted Average Exercise per Share Price	$ 5.35
Range 6 [Member]
Summarizes information with respect to stock options outstanding
Lower Range of Exercise Price	$ 5.41
Upper Range of Exercise Price	$ 5.41
Number of Shares Outstanding and Exercisable	1,186,650
Options outstanding Weighted-Average Remaining Contractual life	9 years 11 months 5 days
Number of Shares Exercisable
Options exercisable Weighted Average Exercise per Share Price
Range 7 [Member]
Summarizes information with respect to stock options outstanding
Lower Range of Exercise Price	$ 5.42
Upper Range of Exercise Price	$ 5.66
Number of Shares Outstanding and Exercisable	60,500
Options outstanding Weighted-Average Remaining Contractual life	6 years 2 months 27 days
Number of Shares Exercisable	56,333
Options exercisable Weighted Average Exercise per Share Price	$ 5.46
Range 8 [Member]
Summarizes information with respect to stock options outstanding
Lower Range of Exercise Price	$ 5.70
Upper Range of Exercise Price	$ 5.70
Number of Shares Outstanding and Exercisable	1,132,851
Options outstanding Weighted-Average Remaining Contractual life	7 years 11 months 9 days
Number of Shares Exercisable	565,551
Options exercisable Weighted Average Exercise per Share Price	$ 5.70
Range 9 [Member]
Summarizes information with respect to stock options outstanding
Lower Range of Exercise Price	$ 5.86
Upper Range of Exercise Price	$ 6.82
Number of Shares Outstanding and Exercisable	1,054,230
Options outstanding Weighted-Average Remaining Contractual life	5 years 10 months 17 days
Number of Shares Exercisable	785,006
Options exercisable Weighted Average Exercise per Share Price	$ 6.49
Range 10 [Member]
Summarizes information with respect to stock options outstanding
Lower Range of Exercise Price	$ 6.88
Upper Range of Exercise Price	$ 14.62
Number of Shares Outstanding and Exercisable	1,590,953
Options outstanding Weighted-Average Remaining Contractual life	4 years 9 months 18 days
Number of Shares Exercisable	1,555,263
Options exercisable Weighted Average Exercise per Share Price	$ 12.59